code: def test_non_neg(self):
      constraint_fn = constraints.NonNeg()
      output = constraint_fn(get_example_array())
      output = backend.convert_to_numpy(output)
      self.assertTrue((np.min(output, axis=1) >= 0.0).all())
  
file_path: keras/keras/constraints/constraints_test.py
imports: import numpy
  from keras import backend
  from keras import constraints
  from keras import testing
label_desc: Use image node_id 2 for calling the ConstraintsTest obj's underlying member method code with example usage: obj.test_non_neg() without return types